COMM Post--Selling Yourself to an Agent or Publisher

I have been working on a query letter and book proposal for two months. I have a list of potential candidates who I will try and impress in the next week. I have the first four paragraphs completed, but am puzzled at how to conclude my last paragraph, an action or non-action, last paragraph. I don't want to come off to demanding, but honest and positive. I never thought three sentences would challenge me. I got some great advice today on how to format and present my query letter. Support is hard to come by these days. Most people are great talkers, but poor in really helping to complete a task.